зеркало из https://github.com/mozilla/gecko-dev.git
624 строки
16 KiB
C++
624 строки
16 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "txNodeSet.h"
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#include "txLog.h"
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#include "nsMemory.h"
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#include "txXPathTreeWalker.h"
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#include <algorithm>
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/**
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* Implementation of an XPath nodeset
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*/
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#ifdef NS_BUILD_REFCNT_LOGGING
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#define LOG_CHUNK_MOVE(_start, _new_start, _count) \
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{ \
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txXPathNode *start = const_cast<txXPathNode*>(_start); \
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while (start < _start + _count) { \
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NS_LogDtor(start, "txXPathNode", sizeof(*start)); \
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++start; \
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} \
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start = const_cast<txXPathNode*>(_new_start); \
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while (start < _new_start + _count) { \
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NS_LogCtor(start, "txXPathNode", sizeof(*start)); \
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++start; \
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} \
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}
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#else
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#define LOG_CHUNK_MOVE(_start, _new_start, _count)
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#endif
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static const int32_t kTxNodeSetMinSize = 4;
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static const int32_t kTxNodeSetGrowFactor = 2;
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#define kForward 1
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#define kReversed -1
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txNodeSet::txNodeSet(txResultRecycler* aRecycler)
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: txAExprResult(aRecycler),
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mStart(nullptr),
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mEnd(nullptr),
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mStartBuffer(nullptr),
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mEndBuffer(nullptr),
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mDirection(kForward),
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mMarks(nullptr)
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{
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}
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txNodeSet::txNodeSet(const txXPathNode& aNode, txResultRecycler* aRecycler)
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: txAExprResult(aRecycler),
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mStart(nullptr),
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mEnd(nullptr),
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mStartBuffer(nullptr),
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mEndBuffer(nullptr),
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mDirection(kForward),
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mMarks(nullptr)
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{
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if (!ensureGrowSize(1)) {
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return;
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}
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new(mStart) txXPathNode(aNode);
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++mEnd;
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}
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txNodeSet::txNodeSet(const txNodeSet& aSource, txResultRecycler* aRecycler)
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: txAExprResult(aRecycler),
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mStart(nullptr),
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mEnd(nullptr),
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mStartBuffer(nullptr),
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mEndBuffer(nullptr),
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mDirection(kForward),
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mMarks(nullptr)
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{
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append(aSource);
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}
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txNodeSet::~txNodeSet()
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{
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delete [] mMarks;
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if (mStartBuffer) {
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destroyElements(mStart, mEnd);
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free(mStartBuffer);
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}
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}
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nsresult txNodeSet::add(const txXPathNode& aNode)
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{
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NS_ASSERTION(mDirection == kForward,
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"only append(aNode) is supported on reversed nodesets");
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if (isEmpty()) {
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return append(aNode);
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}
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bool dupe;
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txXPathNode* pos = findPosition(aNode, mStart, mEnd, dupe);
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if (dupe) {
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return NS_OK;
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}
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// save pos, ensureGrowSize messes with the pointers
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int32_t moveSize = mEnd - pos;
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int32_t offset = pos - mStart;
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if (!ensureGrowSize(1)) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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// set pos to where it was
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pos = mStart + offset;
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if (moveSize > 0) {
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LOG_CHUNK_MOVE(pos, pos + 1, moveSize);
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memmove(pos + 1, pos, moveSize * sizeof(txXPathNode));
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}
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new(pos) txXPathNode(aNode);
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++mEnd;
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return NS_OK;
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}
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nsresult txNodeSet::add(const txNodeSet& aNodes)
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{
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return add(aNodes, copyElements, nullptr);
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}
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nsresult txNodeSet::addAndTransfer(txNodeSet* aNodes)
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{
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// failure is out-of-memory, transfer didn't happen
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nsresult rv = add(*aNodes, transferElements, destroyElements);
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NS_ENSURE_SUCCESS(rv, rv);
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#ifdef TX_DONT_RECYCLE_BUFFER
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if (aNodes->mStartBuffer) {
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free(aNodes->mStartBuffer);
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aNodes->mStartBuffer = aNodes->mEndBuffer = nullptr;
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}
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#endif
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aNodes->mStart = aNodes->mEnd = aNodes->mStartBuffer;
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return NS_OK;
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}
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/**
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* add(aNodeSet, aTransferOp)
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*
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* The code is optimized to make a minimum number of calls to
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* Node::compareDocumentPosition. The idea is this:
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* We have the two nodesets (number indicate "document position")
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*
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* 1 3 7 <- source 1
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* 2 3 6 8 9 <- source 2
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* _ _ _ _ _ _ _ _ <- result
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*
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*
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* When merging these nodesets into the result, the nodes are transfered
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* in chunks to the end of the buffer so that each chunk does not contain
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* a node from the other nodeset, in document order.
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*
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* We select the last non-transfered node in the first nodeset and find
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* where in the other nodeset it would be inserted. In this case we would
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* take the 7 from the first nodeset and find the position between the
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* 6 and 8 in the second. We then take the nodes after the insert-position
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* and transfer them to the end of the resulting nodeset. Which in this case
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* means that we first transfered the 8 and 9 nodes, giving us the following:
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*
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* 1 3 7 <- source 1
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* 2 3 6 <- source 2
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* _ _ _ _ _ _ 8 9 <- result
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*
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* The corresponding procedure is done for the second nodeset, that is
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* the insertion position of the 6 in the first nodeset is found, which
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* is between the 3 and the 7. The 7 is memmoved (as it stays within
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* the same nodeset) to the result buffer.
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*
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* As the result buffer is filled from the end, it is safe to share the
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* buffer between this nodeset and the result.
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*
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* This is repeated until both of the nodesets are empty.
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*
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* If we find a duplicate node when searching for where insertposition we
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* check for sequences of duplicate nodes, which can be optimized.
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*
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*/
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nsresult txNodeSet::add(const txNodeSet& aNodes, transferOp aTransfer,
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destroyOp aDestroy)
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{
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NS_ASSERTION(mDirection == kForward,
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"only append(aNode) is supported on reversed nodesets");
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if (aNodes.isEmpty()) {
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return NS_OK;
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}
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if (!ensureGrowSize(aNodes.size())) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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// This is probably a rather common case, so lets try to shortcut.
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if (mStart == mEnd ||
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txXPathNodeUtils::comparePosition(mEnd[-1], *aNodes.mStart) < 0) {
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aTransfer(mEnd, aNodes.mStart, aNodes.mEnd);
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mEnd += aNodes.size();
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return NS_OK;
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}
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// Last element in this nodeset
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txXPathNode* thisPos = mEnd;
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// Last element of the other nodeset
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txXPathNode* otherPos = aNodes.mEnd;
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// Pointer to the insertion point in this nodeset
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txXPathNode* insertPos = mEndBuffer;
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bool dupe;
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txXPathNode* pos;
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int32_t count;
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while (thisPos > mStart || otherPos > aNodes.mStart) {
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// Find where the last remaining node of this nodeset would
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// be inserted in the other nodeset.
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if (thisPos > mStart) {
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pos = findPosition(thisPos[-1], aNodes.mStart, otherPos, dupe);
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if (dupe) {
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const txXPathNode *deletePos = thisPos;
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--thisPos; // this is already added
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// check dupe sequence
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while (thisPos > mStart && pos > aNodes.mStart &&
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thisPos[-1] == pos[-1]) {
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--thisPos;
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--pos;
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}
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if (aDestroy) {
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aDestroy(thisPos, deletePos);
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}
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}
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}
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else {
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pos = aNodes.mStart;
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}
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// Transfer the otherNodes after the insertion point to the result
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count = otherPos - pos;
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if (count > 0) {
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insertPos -= count;
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aTransfer(insertPos, pos, otherPos);
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otherPos -= count;
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}
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// Find where the last remaining node of the otherNodeset would
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// be inserted in this nodeset.
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if (otherPos > aNodes.mStart) {
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pos = findPosition(otherPos[-1], mStart, thisPos, dupe);
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if (dupe) {
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const txXPathNode *deletePos = otherPos;
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--otherPos; // this is already added
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// check dupe sequence
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while (otherPos > aNodes.mStart && pos > mStart &&
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otherPos[-1] == pos[-1]) {
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--otherPos;
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--pos;
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}
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if (aDestroy) {
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aDestroy(otherPos, deletePos);
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}
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}
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}
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else {
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pos = mStart;
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}
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// Move the nodes from this nodeset after the insertion point
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// to the result
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count = thisPos - pos;
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if (count > 0) {
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insertPos -= count;
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LOG_CHUNK_MOVE(pos, insertPos, count);
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memmove(insertPos, pos, count * sizeof(txXPathNode));
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thisPos -= count;
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}
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}
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mStart = insertPos;
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mEnd = mEndBuffer;
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return NS_OK;
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}
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/**
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* Append API
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* These functions should be used with care.
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* They are intended to be used when the caller assures that the resulting
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* nodeset remains in document order.
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* Abuse will break document order, and cause errors in the result.
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* These functions are significantly faster than the add API, as no
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* order info operations will be performed.
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*/
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nsresult
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txNodeSet::append(const txXPathNode& aNode)
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{
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if (!ensureGrowSize(1)) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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if (mDirection == kForward) {
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new(mEnd) txXPathNode(aNode);
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++mEnd;
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return NS_OK;
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}
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new(--mStart) txXPathNode(aNode);
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return NS_OK;
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}
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nsresult
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txNodeSet::append(const txNodeSet& aNodes)
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{
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NS_ASSERTION(mDirection == kForward,
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"only append(aNode) is supported on reversed nodesets");
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if (aNodes.isEmpty()) {
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return NS_OK;
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}
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int32_t appended = aNodes.size();
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if (!ensureGrowSize(appended)) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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copyElements(mEnd, aNodes.mStart, aNodes.mEnd);
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mEnd += appended;
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return NS_OK;
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}
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nsresult
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txNodeSet::mark(int32_t aIndex)
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{
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NS_ASSERTION(aIndex >= 0 && mStart && mEnd - mStart > aIndex,
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"index out of bounds");
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if (!mMarks) {
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int32_t length = size();
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mMarks = new bool[length];
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NS_ENSURE_TRUE(mMarks, NS_ERROR_OUT_OF_MEMORY);
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memset(mMarks, 0, length * sizeof(bool));
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}
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if (mDirection == kForward) {
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mMarks[aIndex] = true;
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}
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else {
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mMarks[size() - aIndex - 1] = true;
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}
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return NS_OK;
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}
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nsresult
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txNodeSet::sweep()
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{
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if (!mMarks) {
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// sweep everything
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clear();
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}
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int32_t chunk, pos = 0;
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int32_t length = size();
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txXPathNode* insertion = mStartBuffer;
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while (pos < length) {
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while (pos < length && !mMarks[pos]) {
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// delete unmarked
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mStart[pos].~txXPathNode();
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++pos;
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}
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// find chunk to move
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chunk = 0;
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while (pos < length && mMarks[pos]) {
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++pos;
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++chunk;
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}
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// move chunk
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if (chunk > 0) {
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LOG_CHUNK_MOVE(mStart + pos - chunk, insertion, chunk);
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memmove(insertion, mStart + pos - chunk,
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chunk * sizeof(txXPathNode));
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insertion += chunk;
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}
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}
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mStart = mStartBuffer;
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mEnd = insertion;
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delete [] mMarks;
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mMarks = nullptr;
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return NS_OK;
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}
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void
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txNodeSet::clear()
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{
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destroyElements(mStart, mEnd);
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#ifdef TX_DONT_RECYCLE_BUFFER
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if (mStartBuffer) {
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free(mStartBuffer);
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mStartBuffer = mEndBuffer = nullptr;
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}
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#endif
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mStart = mEnd = mStartBuffer;
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delete [] mMarks;
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mMarks = nullptr;
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mDirection = kForward;
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}
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int32_t
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txNodeSet::indexOf(const txXPathNode& aNode, uint32_t aStart) const
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{
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NS_ASSERTION(mDirection == kForward,
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"only append(aNode) is supported on reversed nodesets");
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if (!mStart || mStart == mEnd) {
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return -1;
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}
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txXPathNode* pos = mStart + aStart;
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for (; pos < mEnd; ++pos) {
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if (*pos == aNode) {
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return pos - mStart;
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}
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}
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return -1;
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}
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const txXPathNode&
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txNodeSet::get(int32_t aIndex) const
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{
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if (mDirection == kForward) {
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return mStart[aIndex];
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}
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return mEnd[-aIndex - 1];
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}
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short
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txNodeSet::getResultType()
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{
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return txAExprResult::NODESET;
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}
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bool
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txNodeSet::booleanValue()
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{
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return !isEmpty();
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}
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double
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txNodeSet::numberValue()
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{
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nsAutoString str;
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stringValue(str);
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return txDouble::toDouble(str);
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}
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void
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txNodeSet::stringValue(nsString& aStr)
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{
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NS_ASSERTION(mDirection == kForward,
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"only append(aNode) is supported on reversed nodesets");
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if (isEmpty()) {
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return;
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}
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txXPathNodeUtils::appendNodeValue(get(0), aStr);
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}
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const nsString*
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txNodeSet::stringValuePointer()
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{
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return nullptr;
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}
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bool txNodeSet::ensureGrowSize(int32_t aSize)
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{
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// check if there is enough place in the buffer as is
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if (mDirection == kForward && aSize <= mEndBuffer - mEnd) {
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return true;
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}
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if (mDirection == kReversed && aSize <= mStart - mStartBuffer) {
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return true;
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}
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// check if we just have to align mStart to have enough space
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int32_t oldSize = mEnd - mStart;
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int32_t oldLength = mEndBuffer - mStartBuffer;
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int32_t ensureSize = oldSize + aSize;
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if (ensureSize <= oldLength) {
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// just move the buffer
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txXPathNode* dest = mStartBuffer;
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if (mDirection == kReversed) {
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dest = mEndBuffer - oldSize;
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}
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LOG_CHUNK_MOVE(mStart, dest, oldSize);
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memmove(dest, mStart, oldSize * sizeof(txXPathNode));
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mStart = dest;
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mEnd = dest + oldSize;
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return true;
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}
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// This isn't 100% safe. But until someone manages to make a 1gig nodeset
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// it should be ok.
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int32_t newLength = std::max(oldLength, kTxNodeSetMinSize);
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while (newLength < ensureSize) {
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newLength *= kTxNodeSetGrowFactor;
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}
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txXPathNode* newArr = static_cast<txXPathNode*>
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(moz_xmalloc(newLength *
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sizeof(txXPathNode)));
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if (!newArr) {
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return false;
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}
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txXPathNode* dest = newArr;
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if (mDirection == kReversed) {
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dest += newLength - oldSize;
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}
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if (oldSize > 0) {
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LOG_CHUNK_MOVE(mStart, dest, oldSize);
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memcpy(dest, mStart, oldSize * sizeof(txXPathNode));
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}
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if (mStartBuffer) {
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#ifdef DEBUG
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memset(mStartBuffer, 0,
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(mEndBuffer - mStartBuffer) * sizeof(txXPathNode));
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#endif
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free(mStartBuffer);
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}
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mStartBuffer = newArr;
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mEndBuffer = mStartBuffer + newLength;
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mStart = dest;
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mEnd = dest + oldSize;
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return true;
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}
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txXPathNode*
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txNodeSet::findPosition(const txXPathNode& aNode, txXPathNode* aFirst,
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txXPathNode* aLast, bool& aDupe) const
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{
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aDupe = false;
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if (aLast - aFirst <= 2) {
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// If we search 2 nodes or less there is no point in further divides
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txXPathNode* pos = aFirst;
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for (; pos < aLast; ++pos) {
|
|
int cmp = txXPathNodeUtils::comparePosition(aNode, *pos);
|
|
if (cmp < 0) {
|
|
return pos;
|
|
}
|
|
|
|
if (cmp == 0) {
|
|
aDupe = true;
|
|
|
|
return pos;
|
|
}
|
|
}
|
|
return pos;
|
|
}
|
|
|
|
// (cannot add two pointers)
|
|
txXPathNode* midpos = aFirst + (aLast - aFirst) / 2;
|
|
int cmp = txXPathNodeUtils::comparePosition(aNode, *midpos);
|
|
if (cmp == 0) {
|
|
aDupe = true;
|
|
|
|
return midpos;
|
|
}
|
|
|
|
if (cmp > 0) {
|
|
return findPosition(aNode, midpos + 1, aLast, aDupe);
|
|
}
|
|
|
|
// midpos excluded as end of range
|
|
|
|
return findPosition(aNode, aFirst, midpos, aDupe);
|
|
}
|
|
|
|
/* static */
|
|
void
|
|
txNodeSet::copyElements(txXPathNode* aDest,
|
|
const txXPathNode* aStart, const txXPathNode* aEnd)
|
|
{
|
|
const txXPathNode* pos = aStart;
|
|
while (pos < aEnd) {
|
|
new(aDest) txXPathNode(*pos);
|
|
++aDest;
|
|
++pos;
|
|
}
|
|
}
|
|
|
|
/* static */
|
|
void
|
|
txNodeSet::transferElements(txXPathNode* aDest,
|
|
const txXPathNode* aStart, const txXPathNode* aEnd)
|
|
{
|
|
LOG_CHUNK_MOVE(aStart, aDest, (aEnd - aStart));
|
|
memcpy(aDest, aStart, (aEnd - aStart) * sizeof(txXPathNode));
|
|
}
|